Santhakumar Raja

Rating of a Transformer The name plate of a transformer specifies the rated voltages of primary and secondary windings, the rated currents of primary and secondary windings and the rated volt-amp. Meanings of these specifications are as under: While manufacturing a transformer, insulations are provided to primary and secondary windings. These insulations are such that

Consider a transformer arrangement as shown in figure. N1– Number of primary turns N2 – Number of secondary turns Φm – Maximum value of flux in the core in wb Bm – Maximum value of flux density in the core in wb/m² A –  Area of the core in m² f – Frequency of the

Construction Details A transformer is a static device and its construction is simple as there are no moving parts. The main components of a transformer are The magnetic core. Primary and secondary windings. Insulation of windings. Expansion tank or conservator. Lead and tappings for coils with their supports, terminals and terminal insulators. Tank, oil, cooling

Transformer works on the principle of electromagnetic induction. A transformer is an electrical device, having no moving parts, which by mutual induction transfers electric energy from one circuit to another at the same frequency, usually with changed values of voltage and current. It consists of two windings insulated from each other and wound on a

In practice it is often required to stop a unit driven by dc motors in an exact position or to have the speed of the driven unit suitably controlled during its deceleration. Such requirement is satisfactorily fulfilled by electric braking. Types Regenerative braking Counter-current braking or plugging Dynamic braking Regenerative Braking Regenerative braking with return

There are several forms of braking applicable to the usual types of electric motors. Generally, we can group all electrical braking methods into three types. Regenerative braking Dynamic or Rheostatic braking Plugging or reverse current braking Regenerative braking In the regenerative braking operation, the motor operates as a generator, while it is still connected to

Whenever an electric drive is disconnected from the supply, the speed of the driving motor gradually decreases and becomes zero. Braking is a generic term used to describe a set of operating conditions for electric drive systems. It includes rapid stopping of the electric motor, holding the motor shaft to a specific position, maintaining the

[sc_fs_faq html=”true” headline=”h2″ img=”” question=”Mention speed control methods of DC shunt motors?” img_alt=”” css_class=””] 1. Armature control method, 2. Field control method, 3. Voltage control method [/sc_fs_faq] The speed of a dc motor is given by [latex]N=\frac{V-I_{a} R_{a}}{Z \phi}\left(\frac{A}{P}\right) \text { (or) } \quad N=\frac{K\left(V-I_{a} R_{a}\right)}{\phi} [/latex] where  V = applied voltage, Ia = armature current Ra

There are three types of characteristics. Open circuit characteristics (OCC) or magnetisation characteristics (E2 versus If). Internal characteristics or total characteristics (E versus Ia). External characteristics or voltage regulated characteristics (V versus IL) Separately excited DC generator characteristics For a given dc generator it is clear that the induced emf is proportional to the flux